So, I have this big ass fancy IPOD Classic, the stock OS is, like most of the apple stuff, dogshit; I installed Rockbox and gave him new life.
Yesterday I had some strange errors during theme installation (RockboxUtility on Fedora X86_64), files extraction failed or something like this.
At first I thought of a corrupted Rockbox installation, after a bit of thinkering I found out the thing was just mounted as read only; tried to mount it manually with the rw flag but still a no go.
Umount the volume and run fsck.vfat /dev/sd*2 saved the day, now the IPOD is mountable as rw.